Transmission dynamometer



July 9, 1935. I M JR 2,007,505

/4 7 F/ a 3 i6 l'l'l'F Patented July 9, 1935 UNITED STATES.

PATENT This invention relates to internal combustion engines, but more particularly to a transmission dynamometer, whereby the power transmitted from the driving memberto the driven member of the transmission may be accurately'measured from the resistance to an electrical circuit.

With this object in view, the invention consists of an arrangement of an electrical resistance between the driving and the driven members of a transmission, the resistance of which is a function of the pressure on the element or elements constituting the electrical resistance.

The invention further consists of certain other novel details of constructionand combinations of parts, all of which will be first fully described and afterwards specifically pointed out in'the appended claims. I

Referring to the accompanying drawing:

Figure 1 isa diagrammatic view in elevation of a transmission dynamometer constructed in accordance with this invention;

Figure 2 is a vertical sectional view taken on line 22 of Fig. 1; and v Figure 3 illustrates diagrammatically the ap-' paratus and the electrical circuit.

Like numerals of reference indicate the same parts throughout the several figures, in which:

I indicates a driving member fixed to a shaft}, and 3 is a driven member fixed on a shaft 4,

The driving member I includes aplurality of radial spokes 5 each having two oppositely disposed inclined faces 6, while the driven member 3 is'supplied with an equal number of lugs I projecting from the face of the driven member into the spaces between the said radial spokes 5 of the driving member I. V r

- interposed between each lug I and the adjacent inclined faces of theradial spokes 5 of the driving member, is an electrical resistance element 3, on each side of which I prefer to .interpose a; buifer spring 9 insulated from the resistance 'element 8 by suitable insulating blocks Ill, the' purpose of said springs being to-smooth-out variacally connected by the wires l2, while'the-said resistance elements 8 are themselves electrically tion of series-parallel connections'deslrable or convenient from the standpoint'of ease of use or accuracy of measurement. The accompanying drawing therefore illustrates only one example of such electrical connection.

I! indicates the stationary brushes for electrical contact with the said slip rings ll, towhich brushes l3 areconnectedthe two wires Id and I5 from the battery l6, while arranged in this battery circuit is any'suitable resistance measuring instrument or instruments, suchas Wheatstone bridges, ammeters, voltmeters, oscillographs, etc.

- of is a function of the pressure applied to them,

said elements may, for instance, be made-t9 consistofastackorstacksofcarbondiscs orannular rings ll.

iconnected inseries or or any Having thus described the invention, its. op

eration is as follows:

The parts being as'embled as in the-example shown in the drawing, the pressure from the driving member I is communicated to the driven member 3 through the intermediately disposed resistance elemenis I, so that their resistance is increased or diminished according to the pressure applied thereto. As the voltmeter l1 indicates the constant voltage of the battery ii, the ammeter I! will indicate the change in current in the circuit, which is a direct measure of the change in the resistance of the resistance elements 8, and by calibration indicates the force or pres sure acting on said elements.

Having thus fully described the invention, I do notwishtobe'understoodaslimitingmyselftothe exact construction herein set forth, but I consider myself clearly entitled to all such changes and modiflcaiions as fall within the limit and scope of the appended claims.

WhatIclaimasnewanddesiretosecureby Letters Patent of the United States, is:

1. A device of the character described incluiling a driving member, a driven member, an electrical circuit, the driving member having a plurality of'radial-spok'es, the driven member having a plurality of lugs extending within the spaces between the spokes, a plurality of electrical resistanc'e elements in said circuit and interposed between the said spokes of the driving member and the said lugs of the driven member, said resistance elements including a plurality of carbon members, a buiier spring on each side of each or the resistance elements, means for electrically insulating the resistance elements from said buiIer springs, a source 01' current and means for measuring the electrical resistance of said elements.

2. A dynamometer including a driving member having a plurality of spokes, a driven member having a plurality of lugs extending within the spaces between the spokes, a pair of electrical resistors in each of the said spaces and arranged one on each side oi. the lug, one end of each' resistor being mechanically connected to the lug and the other end being mechanically connected to an adjacent spoke, each oi! said resistors being of a nature such that the electrical resistance thereot is a function of the pressure applied thereto,

means electrically insulating the resistors from the said spokes and lugs, and electrical resistance measuring means connected in electrical circuit with the said resistors.

3. A tron dynamometer comprising a driving member, a driven member, elastic means coupling the said members for transmitting the torque of the driving member to the driven member, said elastic coupling means including an electrical resistance unit of which the electrical resistance is a function of the pressure applied thereto, and tension springs forwardly and rearwardly oi. the resistance unit to yieldably support the latter between the members and to dampen out variations in resistance due to variations in torque transmitted, and resistance measuring means connected in electrical circuit with said resistance unit.

MARSHALL A. SMITH, J]. 20 

